I have been going to NFL games for the better part of 30 years now, and it’s not that uncommon to see up to 25% opposing fans at a stadium these days. It’s a lot more than it used to be, and like some other people mentioned, it’s probably due to the ease of selling the tickets to the highest bitter nationwide on platforms, like Ticketmaster. I would love to sell my tickets to Packer fans only, and I generally do via a couple private Facebook groups. and when I say I go to football games, I don’t only go to Packers games, I often go see random teams play in Philadelphia or New York when I can find a cheap ticket, and there are definitely a lot of opposing fans and all of the stadiums.

A lot of people aren’t going to recognize the sarcasm/irony you’re pointing out here lol